ChatGPT vs. Claude vs. Gemini: I Tested All Three for ESL Lesson Planning (Here’s the Winner)

Every other day, someone in an ESL teachers’ Facebook group asks the same question: “Which AI is best for lesson planning?”

The answers are usually a mess. Half the comments swear by ChatGPT. A third are loyal to Claude. A few brave souls bring up Gemini. And nobody actually shows you the receipts.

So I ran the test myself.

For two weeks, I used ChatGPT (GPT-4o), Claude (Sonnet), and Gemini (1.5 Pro) for the exact same lesson planning tasks. Same prompts. Same student profiles. Same content goals. Then I scored each one across the things ESL teachers actually care about — speed, activity quality, grammar explanations, differentiation, and how much I had to edit before I could put the material in front of students.

Here’s what I found.

The Test Setup

I picked four lesson scenarios that cover most of what ESL teachers plan in a normal week:

• A 60-minute B1 adult conversation lesson on travel
• A grammar lesson on present perfect for B2 learners
• A vocabulary review activity for A2 teenagers
• A differentiated reading lesson for a mixed-level (A2–B1) class

For each scenario, I used the exact same starting prompt across all three AIs. Then I judged the outputs on five dimensions:

• How fast I got something usable
• How creative and class-ready the activities were
• How clearly grammar was explained for non-native speakers
• How well it handled mixed-level classes
• How much editing I had to do before I’d use it

No tricks. No tweaking the prompt to favor one tool. Same input, different brains.

Round 1: Speed to a Usable Lesson

This is the round most teachers care about. You don’t have time to coax a tool into giving you something good — you need it now, between classes, with a coffee in one hand.

Claude won this round, but barely. The first draft was the most “ready” — clear timing, logical lesson stages, and a warm-up I’d actually use. ChatGPT was a close second; the structure was solid, but the warm-up felt generic. Gemini gave me a great outline but kept including weirdly British phrases for an American audience (and weirdly American phrases for a British audience — almost like it can’t pick a lane).

Winner: Claude. Honorable mention: ChatGPT.

Round 2: Activity Quality

This is where it got interesting. ChatGPT’s activities were the most creative — at one point, it suggested a “travel agent role-play with a problem customer” that I genuinely loved. Claude’s activities were solid and pedagogically tighter, but a little safer. Gemini’s activities felt copy-pasted from a 2018 textbook.

Winner: ChatGPT. The pattern: Claude is the better lesson planner, ChatGPT is the better idea generator.

Round 3: Grammar Explanations

If you’ve ever asked an AI to explain present perfect to a B2 student, you know how badly this can go. The metalanguage gets out of control. Suddenly, your students are reading “the present perfect describes an unspecified event in the past with present relevance” and you’re explaining the explanation.

Claude was the clear winner here. The grammar explanations were short, used real examples, and stayed in language a B2 learner could read without a dictionary. ChatGPT tended to get academic. Gemini gave me a textbook definition and stopped.

Winner: Claude.

Round 4: Differentiation

For the mixed-level reading lesson, I asked each AI to produce three versions of the same comprehension task — one for A2, one for B1, and one for early B1+ — using the same passage.

ChatGPT did this best. It actually changed sentence structure, vocabulary, and task type across the levels. Claude differentiated the questions but kept the task too similar across the three groups. Gemini just shortened the questions for the lower level, which isn’t differentiation — it’s defeat.

Winner: ChatGPT.

Round 5: Free Plan Generosity

Most ESL teachers are paying for one tool, max. So which gives you the most for nothing?

• Claude.ai: solid free tier, no Pro subscription needed for most lesson planning
• ChatGPT: free plan includes GPT-4o with limits — generous, but you’ll hit the cap on a heavy planning day
• Gemini: technically, the most generous free plan, but the output quality drops off the most

Winner (free use): Claude. Winner (paid power user): ChatGPT Plus, by a small margin.

The Verdict

If you’re choosing one tool, the answer depends on what you do most.

For most ESL teachers, Claude is the best all-rounder. The lesson plans need the least editing, the grammar explanations are student-friendly, and the free plan is enough for a full teaching week.

If you live for creative activities and role-plays, go with ChatGPT. The ideas are more inventive, and the differentiation is genuinely better.

Skip Gemini for now, unless you’re already deep in the Google ecosystem. The output quality just isn’t there yet for ESL-specific work.

The Boring Truth Nobody Wants to Hear

Here’s what two weeks of testing actually taught me: your prompt matters more than your tool.

A well-structured prompt in Gemini will beat a one-liner in Claude every time. The reason most teachers think AI is “meh” for lesson planning isn’t the AI, it’s the prompts.

When I gave each tool a vague prompt like “make me a lesson on travel for B1 adults,” all three produced average work. When I gave the exact same tool a prompt that specified the learner profile, lesson stage, target language, timing, and the mistakes I wanted students to avoid, the output was unrecognizable. Genuinely usable. Often better than what I’d write myself on a Sunday night.

So pick the tool that fits your budget and your workflow. Then put your time into building a small library of prompts that work.

Free Resource: 50 ESL Prompts That Work in Any AI

If you don’t want to spend the next three months writing and testing prompts yourself, I built a free PDF of the 50 prompts I use most. They work in ChatGPT, Claude, and Gemini — and each one comes with a “why it works” explanation so you can adapt them to your context.

And if you want done-for-you classroom activities you can use tomorrow morning, the Ultimate ESL Activity Bundle gives you 14 ready-to-run lessons across speaking, grammar, vocabulary, and writing.

Get the Ultimate ESL Activity Bundle on Gumroad